As communications base stations are highly integrated, there is a growing demand for multiplexers. For a multiplexer, a core technology is an input/output apparatus of the multiplexer. In the prior art, each tap in an input/output apparatus is connected to a resonant cavity by means of welding.
From a perspective of receiving signals by a base station, a signal received by an antenna enters a multiplexer from an input/output apparatus of the multiplexer; and signals of different frequencies flow into multiplexer channels of different frequencies. Because a difference between the frequencies of the signals on the channels is generally small, signal interference between the channels is very high. In contrast, from a perspective of outputting signals from the multiplexer, the same applies to a reverse process, that is, signal interference between the channels is very high.
In the prior art, to reduce signal interference between channels, a fly lever is added to a resonant cavity for phase adjustment. Signal interference between channels is reduced by means of phase adjustment. However, because phase adjustment is hard in this mode, signal interference between channels cannot be completely eliminated.